The present invention relates to a technology for manufacturing a semiconductor device. More particularly, it relates to a technology effective for the formation of a copper plating film by an electroplating device.
In a manufacturing process of a semiconductor device, there is employed a deposition technology in which wirings are formed using an electroplating method. The deposition process referred to as the electroplating method is a process in which copper (Cu) wirings for coupling electronic devices are formed by using an electroplating device.
With the electroplating device, a semiconductor wafer with a cathode arranged thereon is set downwardly with respect to a plating bath, and is immersed in a plating solution. Thus, a voltage is applied to the cathode and an anode arranged in such a manner as to face the semiconductor wafer. This causes a current to flow from the semiconductor wafer peripheral part through a seed film (conductive thin film), thereby to grow a copper plating film on the entire surface of the semiconductor wafer.
During plating deposition, the amount of copper precipitated in the plating solution is determined by the cumulative charge amount. For this reason, voltage control is performed so that the current flowing across anode—cathode becomes constant. Thus, the uniformity of the copper plating film thickness is kept.
For this kind of deposition technology, for example, the following are known: a technology in which during plating deposition of damascene wirings and the like, the bottom-up amount in the wirings, and the amount of impurities included in the copper plating film are kept constant, thereby to suppress the variations in electrical characteristics of the semiconductor device (see, e.g., Patent Document 1); and a technology in which the concentrations of the promoter, the inhibitor, and chlorine in the plating solution are detected, and the promoter concentration, the inhibitor concentration, and the chlorine concentration in the plating solution are set at respective prescribed concentrations, thereby to keep the plating solution with a prescribed concentration (see, e.g., Patent Document 2).